-Larry
1) MyBO's SQL table has a field called "field1"
2) You customize "field1" to, say, trim the value.
3) You change the structure of the SQL table so that "field1" no longer exists (or was renamed).
4) The BOMapper thinks the field disappeared, but the customization record still exists within the BOMapper.
So, the warning is just telling you that not all of the fields that you customized are being created on the business object.
As for your other error, can you post the red error message that contains the stack trace... might tell us where that exception is being thrown from